1. Technical Field
The present invention relates to a suction device that has a plurality of head caps capable of closely contacting with and moving away from corresponding nozzle surfaces of a plurality of inkjet functional liquid droplet ejection heads, and a liquid droplet ejection apparatus having the suction device, as well as an electro-optical apparatus and a manufacturing method thereof.
2. Related Art
It is known that suction devices have seven suction units having twelve head caps mounted thereon, corresponding to seven carriage units having twelve functional liquid droplet ejection heads mounted thereon (see, for example, JP-A-2005-254798).
Each suction unit includes a cap unit that has twelve head caps mounted on a cap plate, a contacting/separating mechanism that contacts/moves the twelve head caps with/away from twelve functional liquid droplet ejection heads by using the cap plate, a waste liquid tank that communicates to the twelve head caps, an ejector that has a secondary side connected to the waste liquid tank to apply suction pressure to the waste liquid tank, and a suction channel that connects the twelve head caps to the waste liquid tank.
When compressed air is introduced to a primary side of the ejector to drive the ejector while the head caps are closely contacted with their corresponding functional liquid droplet ejection heads, inside the waste liquid tank and the suction channel are under negative pressure so that the functional liquid is sucked from the twelve functional liquid droplet ejection heads via the twelve head caps.
In such suction devices, when some functional liquid droplet ejection heads out of the twelve functional liquid droplet ejection heads require suction because of clogging and the like while others do not, the devices collectively perform suction process so that functional liquid is wasted. In such a case, it is conceivable that an open/close valve is disposed on an individual suction channel in each of the functional liquid droplet ejection heads to suck only the functional liquid droplet ejection heads that need to be sucked.
However, it is presumed that, in this configuration, if the number of the functional liquid droplet ejection heads subjected to the suction is changed, suction force in each head caps is varied (change in suction flow rate), which can make it impossible to appropriately suck each functional liquid droplet ejection head.